On Sun, Aug 25, 2013 at 7:56 PM, Lei Wen <adrian.w...@gmail.com> wrote: > On Tue, Aug 20, 2013 at 12:01 AM, Peter Zijlstra <pet...@infradead.org> wrote: >> From: Joonsoo Kim <iamjoonsoo....@lge.com> >> >> There is no reason to maintain separate variables for this_group >> and busiest_group in sd_lb_stat, except saving some space. >> But this structure is always allocated in stack, so this saving >> isn't really benificial [peterz: reducing stack space is good; in this >> case readability increases enough that I think its still beneficial] >> >> This patch unify these variables, so IMO, readability may be improved. >> >> Signed-off-by: Joonsoo Kim <iamjoonsoo....@lge.com> >> [peterz: lots of style edits, a few fixes and a rename] >> Signed-off-by: Peter Zijlstra <pet...@infradead.org> >> Link: >> http://lkml.kernel.org/r/1375778203-31343-4-git-send-email-iamjoonsoo....@lge.com >> --- >> kernel/sched/fair.c | 225 >> +++++++++++++++++++++++++--------------------------- >> 1 file changed, 112 insertions(+), 113 deletions(-) >> >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -4277,36 +4277,6 @@ static unsigned long task_h_load(struct >> > [snip]... >> - env->imbalance = DIV_ROUND_CLOSEST( >> - sds->max_load * sds->busiest->sgp->power, SCHED_POWER_SCALE); >> + env->imbalance = DIV_ROUND_CLOSEST(sds->busiest_stat.avg_load * >> + sds->busiest->sgp->power, SCHED_POWER_SCALE); >> > > I am wondering whether we could change this line as below is more appropriate, > since it would avoid the division here: > env->imbalance = (sds->busiest_stat.avg_load * > sds->busiest->sgp->power) > >> SCHED_POWER_SHIFT; > > I am not sure whether compiler would be smarter enough to covert into >>> operation, > if it see SCHED_POWER_SCALE is 1024 here.
This would change the rounding. Fortunately, gcc is smart enough to handle this. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
